<template>
    <div class="app-container">

        <!--查询表单-->
        <el-form :inline="true" class="demo-form-inline">

            <!-- 所属分类：级联下拉列表 -->
            <!-- 一级分类 -->
            <el-form-item label="课程类别">
                <el-select v-model="searchObj.subjectParentId" placeholder="请选择" @change="subjectChanged">
                    <el-option v-for="subject in subjectList" :key="subject.id" :label="subject.title"
                        :value="subject.id" />
                </el-select>

                <!-- 二级分类 -->
                <el-select v-model="searchObj.subjectId" placeholder="请选择">
                    <el-option v-for="subject in subjectChildrenList" :key="subject.id" :label="subject.title"
                        :value="subject.id" />
                </el-select>
            </el-form-item>

            <!-- 标题 -->
            <el-form-item>
                <el-input v-model="searchObj.title" placeholder="课程标题" />
            </el-form-item>
            <!-- 讲师 -->
            <el-form-item>
                <el-select v-model="searchObj.teacherId" placeholder="请选择讲师">
                    <el-option v-for="teacher in teacherList" :key="teacher.id" :label="teacher.name" :value="teacher.id" />
                </el-select>
            </el-form-item>

            <el-button type="primary" icon="el-icon-search" @click="fetchData()">查询</el-button>
            <el-button type="default" @click="resetData()">清空</el-button>
        </el-form>
        <!-- 表格 -->
        <el-table v-loading="listLoading" :data="list" element-loading-text="数据加载中" border fit highlight-current-row
            row-class-name="myClassList">

            <el-table-column label="序号" width="70" align="center">
                <template slot-scope="scope">
                    {{ (page - 1) * limit + scope.$index + 1 }}
                </template>
            </el-table-column>

            <el-table-column label="封面" width="200" align="center">
                <template slot-scope="scope">
                    <img :src="scope.row.cover" alt="scope.row.title" width="100%" />
                </template>
            </el-table-column>

            <el-table-column label="课程信息">
                <template slot-scope="scope">
                    <a href="">{{ scope.row.title }}</a>
                    <p>
                        分类:{{ scope.row.subjectParentName }} > {{ scope.row.subjectName }}
                    </p>
                    <p>
                        课时:{{ scope.row.lessonNum }} /
                        浏览:{{ scope.row.viewCount }} /
                        付费学员:{{ scope.row.buyCount }}
                    </p>
                </template>
            </el-table-column>

            <el-table-column label="讲师" width="100" align="center">
                <template slot-scope="scope">
                    {{ scope.row.teacherName }}
                </template>
            </el-table-column>
            <el-table-column label="价格" width="100" align="center">
                <template slot-scope="scope">
                    {{ Number(scope.row.price) === 0 ? '免费' :
                        '¥' + scope.row.price.toFixed(2) }}
                </template>
            </el-table-column>
            <el-table-column prop="status" label="课程状态" width="100" align="center">
                <template slot-scope="scope">
                    <el-tag :type="scope.row.status === 'Draft' ? 'warning' : 'sucees'">
                        {{ scope.row.status === 'Draft' ? '未发布' : '已发布' }}
                    </el-tag>
                </template>
            </el-table-column>
            <el-table-column label="创建时间" align="center">
                <template slot-scope="scope">
                    {{ scope.row.gmtCreate.substr(0, 10) }}
                </template>
            </el-table-column>

            <el-table-column label="操作" width="300" align="center">
                <template slot-scope="scope">
                    <router-link :to="'/course/info/' + scope.row.id">
                        <el-button type="primary" size="mini" icon="el-icon-edit">编辑</el-button>
                    </router-link>
                    <router-link :to="'/course/chapter/' + scope.row.id">
                        <el-button type="text" size="mini" icon="el-icon-edit">编辑大纲</el-button>
                    </router-link>
                    <el-button type="danger" size="mini" icon="el-icon-delete"
                        @click="removeById(scope.row.id)">删除</el-button>
                </template>
            </el-table-column>
        </el-table>

        <!-- 分页 -->
        <el-pagination @current-change="changeCurrentPage" @size-change="changePageSize"
            layout="sizes,prev, pager, next,jumper, ->, total" :current-page="page" :page-sizes="[5, 10, 20]"
            :page-size="limit" :total="total" style="padding: 30px 0; text-align: center">
        </el-pagination>
    </div>
</template>

<script>
import courseApi from '@/api/course'
import teacherApi from "@/api/teacher";
import subjectApi from '@/api/subject'

export default {
    data() {
        return {
            listLoading: true, // 是否显示loading信息
            list: [], // 课程列表
            total: 0, // 总记录数
            page: 1, // 页码
            limit: 10, // 每页记录数
            searchObj: { //查询条件
                subjectId: ''
            },
            teacherList: [], // 讲师列表
            subjectList: [], // 课程分类一级列表
            subjectChildrenList: [],// 课程分类二级列表
        }
    },
    created() {
        this.fetchData()
        this.initSubjectList()
        this.initTeacherList()
    },
    methods: {
        fetchData(page = 1) {
            // 当点击分页组件的切换按钮的时候，会传输一个当前页码的参数page
            // 解决分页无效问题
            this.page = page
            this.listLoading = true
            courseApi.getPageList(this.page, this.limit, this.searchObj).then(response => {
                // debugger 设置断点调试
                if (response.success === true) {
                    this.list = response.data.rows
                    this.total = response.data.total
                }
                this.listLoading = false
            })
        },
        // 获取讲师列表
        initTeacherList() {
            teacherApi.list().then(response => {
                this.teacherList = response.data.items
            })
        },
        // 获取课程分类列表
        initSubjectList() {
            subjectApi.getNestedTreeList().then(response => {
                this.subjectList = response.data.items
            })
        },
        // 切换一级类别下拉列表
        subjectChanged(value) {
            this.subjectList.forEach(subject => {
                if (subject.id === value) {
                    this.searchObj.subjectId = ''
                    this.subjectChildrenList = subject.children
                }
            })
        },
        // 重置表单
        resetData() {
            this.searchObj = { subjectId: '' }
            subjectChildrenList = []
            this.fetchData()
        },
        // 当前页修改
        changeCurrentPage(page) {
            this.page = page;
            this.fetchData(page);
        },
        // 每页数修改
        changePageSize(pageSize) {
            this.limit = pageSize;
            this.fetchData();
        },
        removeById(id) {
            this.$confirm('此操作将永久删除该课程，以及该课程下的章节和视频，是否继续', '提示', {
                confirmButtonText: '确定',
                cancelButtonText: '取消',
                type: 'warning'
            }).then(() => {
                return courseApi.removeById(id)
            }).then(response => {
                this.fetchData()
                this.$message(response.message)
            }).catch((response) => { // 失败
                if (response === 'cancel') {
                    this.$message.info('已取消删除')
                }
            })
        },
    }
}
</script>


<style scoped>
.myClassList .info {
    width: 450px;
    overflow: hidden;
}

.myClassList .info .pic {
    width: 150px;
    height: 90px;
    overflow: hidden;
    float: left;
}

.myClassList .info .pic a {
    display: block;
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
}

.myClassList .info .pic img {
    display: block;
    width: 100%;
}

.myClassList td .info .title {
    width: 280px;
    float: right;
    height: 90px;
}

.myClassList td .info .title a {
    display: block;
    height: 48px;
    line-height: 24px;
    overflow: hidden;
    color: #00baf2;
    margin-bottom: 12px;
}

.myClassList td .info .title p {
    line-height: 20px;
    margin-top: 5px;
    color: #818181;
}
</style>